Signaling system



March 18 1924.

Fig. 2.

Invent/6r:

William C. White, by

his Attorney.

Patented Mar. 18, 1924.

UNITED STATES.

7 1,487,301 PATENT oi-Flee.

WILLIAM '0. WHITE; or SCHENECTADY, NEW YORK, as xenon TO GENERAL ELECTRIC COMPANY, a-conronarron or it w YORK.

SIGNALING SYSTEM.

Application filed January 31, 1919, Serial No. 274.,288. Renewed August 14, 1923.

To all whom it may concern:

Be it known that I, WILLIAM C. WHITE, a citizen of the United States, residin at Schenectady, county of Schenectady, tate of New York, have invented certain new and useful Improvements in Signalin Systems, of which the following-is a speci cation.

This application is a continuation in art of my prior application, Serial No. 46, 69, filed August 23, 1915.

My .present invention relates to a 'signaL ing system, and more especially to means for transmittin wireless signals.

One of the o jects of my invention is to provide means for producing continuous electrical waves and means for varying the amplitude of the waves thereby produced. A more articular object of my invention is .to provi e means for varying the amplitude of or modulating the continuous waves in accordance with variations in sound waves. In carrying my invention into efi'ect I preferably em loy an electron discharge device for producing continuous electrical waves in an antenna. If such a device is supplied with a direct current source of constant potential and suitable circuit connections made thereto it maybe made to produce continuous electrical waves of prac- If, however, the potential supplied thereto isvariable, the amplitudeof thewaves pro-' duced Will vary in accordance with the potential variations in the source of supply. Hence if the potential of the supply source tions in sound waves the amplitude of the waves produced may be caused to vary accordingly. L v In my prior application, Serial No. 16,769, filed August 23, 1915, I .have claimed broadly the method of modulation which consists in varying the potential supplied tically constant amplitude in the antenna.

is caused to vary in accordance. with va'rialieve to be novel are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings in which Fig. 1 illustrates diagrammatically one Way in which my invention may be carried into effeet, and Fig. 2 shows a modification thereof.

As indicated in Fig. 1 of the drawings, the means for producing continuous electrical waves in the antenna- 1 comprises an electron discharge device 2 consisting preferably of a highly evacuated envelope having therein a cathode 3 of filamentary form, an anode 4, and a, conducting body 5, which is preferably in the form of a grid interposed between the cathode and anode. Current for the operation of the device is supplied to the clrcuit between the cathode and anode by means of the secondary 6 of the transformer 7. Theeircuitbetween cathode and anode also contains an inductance 8 which is inductively related to the inductance 9 in theantenna. The circuit which includes the cathode, 3 and the grid 5 contains an inductance 10 which is inductively related to the inductance 11 in the antenna. The coupling between 8 and 9 is preferably close, while that between 10 and-11 may in some cases be made very loose. The battery 12 may be employed for adjusting the normal potential of thegrid 5 to a value which is most suitable for the efficient operation of the device. The circuit which comprises the secondary 6, the inductance 8, the anode 1,

and the cathode 3, for convenience or description, I designate the plate circuit. The

circuit which comprises the gird 5, induc-- supplied to the plate circuit of the device 2 by means of the secondary 6 of .the transformer 7, the device 2 will produce continuous electrical waves in the/antenna. When the direction of the current issuch thatthe anode 4 is positive, current flows in the plate ircuit and a potential is induced in e011 9 and in the antenna. This produces a corresponding induced potential in coil 10 and varies the potential of the controlling grid 5. This change in potential in turn pro duces a variation in the plate circuit. When the potential induced in the grid circuit causes the grid to become more negative the current flowing in the plate circuit is decreased while'an induced potential which makes the grid more positive increases the current flow in the plate circuit. These variations in the current in the plate circuit produce an alternating current in the antenna, the frequency of which will be the same as the frequency to which the antenna is tuned. The amplitude of the high frequency-waves thus produced in the antenna. will, among other things, depend upon the potential produced in the secondary 6 of the transformer 7 and the amplitude of the oscillations will vary in accordance with variations in this potential. In order to vary the potential in the plate circuit of the device 2 in accordance with variations in sound waves, the current produced in the local circuit of a telephone transmitter 14 is impressed through a transformer 15 upon the grid circuit of an electron discharge device 16, the construction of which is similar to that of the device 2. The plate circuit of the device 16 is supplied with current from a direct current source 17 and .the current flowing in the plate circuit of the device 16 will be a pulsating current which varies in accordance with the variations in the current in the local circuit of the telephone transmitter 14. 'spulsating current flows through the primary 18 of trans, former 7 and produces a low frequency alternating modulating current in the secondary 6 of the transformer -7. This alternating current will of course vary in accordance,- with the variations in the telephone current. As a result the high frequency current produced by device 2 will vary in amplitude in accordance with variations in the amplitude of the telephone current. When the direction .of the potential in the plate circuit of device 2 is suchthat the anode 4 becomes negative no current will flow in the plate circuit of the device, 2, and hence no high frequency oscillations will be produced. As a result waves willxbe produced only during every other half cycle of the low frequency signaling current produced in the secondary 6 of the transformer 7. It is possible to transmit speechby means of waves of this nature though the articulation may not be as perfect as it would be in fcase both half waves of the low frequency.

current were employed for producing high.

frequency current.

By the arrangement shown in Fig. 2 the disadvantage pointed out above may be avoided. Inthis case, as indicated, two

electron discharge devices 19 and 20 are employed, each of which is connected to the antenna 1 in a manner similar to the connection of device 2, as shown in Fig. l. The inductance 8 is common to the plate circuits of both devices 19 and 20, but separate coils 21 and 22 are used for the grid circuits ,of these devices, these coils being oppositely coupled to'the antenna coil 11. In this case the telephone current from transmitter 14 is impressed directly upon the plate circuits former 23, although, if desired, an amplifier may be used in the same manner as indicated in Fig. 1. The current produced in-the secondary of transformer 23 will of course be a low frequency alternating current of the same nature as that produced in the secondary 6 of the transformer 7 in the arrangement shown in Fig. 1. It will be noted, however, that devices 19 and 20 are oppositely connected to the secondary of transformer 23 so that during one half wave of the low frequency alternating current one of these devices will operate to produce high frequency current while during the other half wave thesecond device will operate to produce high frequency currents. Thus both positive and negative half waves of the low frequency alternating signaling current will be effective in controlling the production of arran ements described the amplitude. of.

the high frequency waves produced in the antenna will fall to zero when the amplitude of the si aling wave becomes zero. The wave pro uced by the system which I have described is in effect a continuous wave which is modulated bythe signaling current.

,of the two devices by means of the trans- It may properly be said of such a wave that it is damped by the modulating wave only in contradistinction to a modulated wave produced by the spark system or other system which is not adapted to produce undamped waves. r

- The system which I have described also is of particular advantage for use in carrying on duplex signaling because of the fact that high frequency waves are supplied to the antenna only while the transmitter 14 is active. At other times the antenna is incondition for receiving signals without disconnecting the transmitting apparatus.

If desired the coilll may be omitted and the coils 10, 21 and 22 be inductively related to coil 9. In most cases, however, I find. that the arrangement shown is preferable as by connecting the circuits in this way the amplitude of the oscillations produced is greater than if coil 10 were coupled to coil 9. This may be due to the'fact that the phase relation of cufrentsin the grid and plate circuits with this arrangement is somewhat different than when coils 10, 21 and '22 are directly coupled to coil 9 and that this difference causes an increase in the amplitude of the oscillations produced.

In the operation of thesystem which I have described when the potential induced in the plate circuit by reason of the action of the sound waves in the telephone transmitter is such as to cause an increase in the current in the plate circuit, there will be a corresponding increase in the current in the antenna. As a result the current induced in the grid circuit will increase correspondingly. The potential upon the grid will be increased and a further increase in the amplitude of the late current will be effected thereby. With the proper ad-,

justment this accumulative effect may be useful. to a large extent in increasing the variations in the. amplitude of the waves producedin the antenna.' Under some conditions, however, this'efi'ect may become so great as to impair the articulation of the speech or other sounds transmitted.

While I have shown and described two modifications of my invention illustrating its utility for wireless teleplion I do not wish to be limited to the particu artarrangements shown as it will be apparent that many variations in the connections used may be made without departing from the scope of the appended claims, and that it may equally well be used for thewireless'trans mission of other signals than sound waves, or for the transmission f sound or other signals through wire circuits.

at I claim as new and desire to secure by Letters Patent of the United States, is

1. In a high frequency signaling system the method of transmission which consists in producing a low frequency alternating mo 'ulatmg signal wave, generating to the exclusion of other high frequency waves, a high frequency wave which when produce will vary in accordance with said low frequency modulating wave, which is damped by the modulatinglwave only, and which falls-to zero when the amplitude of the modulating' 'signal wave becomes zero and in transmitting 'said "high frequency wave.

2. In a high frequency signaling system the method of transmission which consists in producing a low frequency alternating modulating signal wave,. controlling by means of said signal wave the generation of a high frequency wave and thereby generating to the exclusion-of other high frequency wavesa high frequency wave which" when produced will vary in accordance with said low frequency modulating wave, which is v damped by the modulating wave only, and

which falls tozero when the amplitude of the modulating signal wave becomes zero and in transmitting said hlgh frequency.

wave.

3. The method of operating a signaling system which comprises an electron discharge device having grid and plate circuits coupled together for producing oscillations which consists in supplying to the plate circuit of said device a low frequency signal-,

ing current and thereby causing said device to produce high frequency oscillations which vary in amplitude in accordance with the. am litude of the signaling current and .the electron discharge device to produce a high frequency wave whose amplitude varies in accordance with said low frequency Sig-- naling wave, and which falls to zero when the amplitude of the signaling wave becomes zero and in transmitting said high frequency wave.

5. In a high frequency signaling system which comprises, an electrondischarge device, the method whlch consists in producing a low frequency alternatlng slgnaling wave,

.applying this low frequency wave to the electron discharge device and thereby controlling the production of a high frequency wave which when produced will vary in accordance with said low frequency signaling wave, and which falls to zero when the amplitude of the signaling wave becomes zero and in transmitting said high frequency .wave. s

6. In a high frequency signaling system, the combination of a source of low frequency alternating ating signal waves, a

high frequency alternating current, generat or adaptedto generate sustained undainped oscillations, means for controllinggt'he action of said generator so that when oscillations are generated they will vary in amplitude in accordance with said low frequency modulating waves and fall to zero when the amphtude of the modulating wave becomes zero and means for transmitting said oscillations to the exclusion of other high frequency oscillations. Y

7. In a high frequency signaling system, the combination of a source of low frequency alternating modulating signal waves, means comprising an electron discharge device for,

producing sustained undamped oscillations, means for controlling the action of said oscillation producing means so that when oscillations are produced thereby they will vary in amplitude in accordance with said low frequency modulating waves, and

fall to zero when the amplitude of the modulating, waves becomes zero, and means for transmitting said oscillations to the exclusion of other high frequency oscillations.

8. In a high frequency signaling system, the combination of a source of low frequency alternating modulating signaling waves, an electron discharge device having coupled grid and plate circuits for producing high' frequency oscillations, means for supplying to the plate circuit of said device low frequency signaling waves, and thereby causing said device to produce high frequency oscillations which vary in amplitude in accordance with the amplitude of the signaling waves, and which fall to zero when the amplitude of said signaling waves becomes zero, and means for transmitting .tlie high frequency oscillations thus produced.

9. The combination with a thermionic oscillator having a pair of anode circuits, of telephonic means supplying energy to said anode circuits which respectively select the positive and negative energy delivered by said means.

10. The combination with a thermionic oscillator having a pair of anode circuits, of

a transfori'ner whose secondary is connected to said anode circuits, and means for supplying modulated energy to said transformer including a source of continuous current, and

' means for varying the current from said source in accordance with sound waves.

11. The combination with an, electron discharge oscillator having a pair of plate 011'- cuits, of means for supplying energy modulated in accordance with sound waves to said plate circuits in such a way that energy comting medium.

13. The method of electrically ransmitting sound waves, which consists in producing electrical energy modulated in accordance with sound waves and comprising components of opposite polarities, impressing the components of different polarities upon differentoscillators to produce different groups 'of oscillations, varying in amplitude. in accordance with sound waves, and impressing energy of the oscillations of the different groups upon a transmitting medium.

14. The method of electrically transmitoscillations whose envelope is uninterrupted and representative of the sound waves, and

impressing energy of the oscillations of the different groups upon a transmitting medium. 4

15. The combination with a pair of oscillators, of means for producing energy modulated in accordance with sound waves and having positive and negative components,

means for impressing the componentsof dif-.

ferent polarities upon different of said oscillators, and means for impressing energy of the different groups of oscillations upon a transmitting medium.

16. The combination with a pair of oscillators producing oscillations of the same frequency, of means for producing energy modulated in accordance with sound waves and having positive and negative components, means for impressing the components of different polarities upon different of said oscillators, and means for impressing energy of the different groups of oscillations upon a transmitting medium.

17. The combination with a pair of thermionic oscillators, of means producing electrical energy modulated in accordance with sound waves and having components of different polarities, means for supplying the components of diflerent polarities to different of said oscillators, whereb the envelope of the successive groups of oscillations is continuous, and means for impressing energy of the successive groups of oscillations upon a transmitting medium.

18. In a high frequency signaling system the method of transmission which consists in producing a low frequency alternating modulating signal wave, generating to the exclusion of other high frequency vaves' and solely by energy supplied by said signal wave, a high frequency 'wave which when produced will vary in accordance with said low frequency signal wave, and in transmitting said high frequency wave.

19. In a high frequency signaling system the method of transmission which consists in producing a. low frequency alternating modulating signalv wave, controlling by means of said signal wave the generation of a high frequency waye which is produced solely by energy supplied by said signal wave and thereby generating to the exclusion of other high frequency waves a high f re quency wave which when produced will vary in accordance with said low frequency signal wave and in transmitting said high frequency wave. V

20. The method of operating a signaling s stem which comprises an electron discharge evice having grid and plate circuits coupled together for producing oscillations which consists in supplying to the plate circuit of said device a low frequency signaling current only and thereby causing said device to produce high frequency oscillations which vary in amplitude in accordance with the amplitude of the signaling current and in transmitting the high frequency oscillations thus produced.

21. In a high frequency signaling system which comprises an electron discharge device, the method which consists in producing a low frequency alternating signaling wave, applying this low frequency wave only to the electron discharge device to produce a high frequency wave whose amplitude varies in accordance with said low frequency "signaling wave and in transmitting said high frequency wave.

22. In a high frequency signaling system which comprises an electron discharge device, the method which consists in producing a low frequency alternating signaling wave, applying this low frequency wave to the electron dischar e device and thereby controlling the production of a high frequency wave which is produced solely by energy supplied by said signaling wave, and which when produced will vary in accordance with said low frequency signaling wave, and in transmitting said high frequency wave.

23. In a high frequency signaling system the combination of a source of low fre quency alternating modulating signal waves, a high frequency alternating current generator adapted to generate sustained undamped oscillations, means for controlling the action of said generator so that when oscillations are generated they will be produced solely from energy supplied by said low frequency signal waves and will vary in amplitude in accordance with said low frequency waves and means for transmitting said oscillations to the exclusion of other high frequency oscillations.

24. In a high frequency si-gn-alin system, the combination of a source of low f i'equency alternating modulating signal waves, means comprising an electron discharge device for producing sustained undamped oscillations, means for controlling the action of said oscillation producing means so that when oscillations are produced thereby they will be produced solely from energy supplied from said low frequency source and will vary inamplitude in accordance with said low frequency modulating waves, and means for transmitting said oscillations to the ex: clusion of other high. frequency oscillations 25. In a high frequency signaling system, the combination of a source of low frequency modulating signaling waves, an electron discharge device having couple-d plate and grid circuits for producing high 'fre-' quency oscillations, means for supplyingto the plate circuit of said device low frequency signaling waves only and thereby causing said device to produce high frequency oscillations which vary in amplitude in accordance with the amplitude of the signaling Wave, and means for transmitting the high frequency oscillations thus produced.

26. In a high frequency signaling system the method which consists in producing a low frequency signal wave, generating solely by mean-s of energy supplied by said low frequency signal wave a high frequency wave which varies in amplitude in accordance with said low frequency Wave and transmitting said high frequency wave.

27. The method of operating a signaling. system which comprises an electron discharge device having grid and plate circuits coupled together for producing oscillations which consists in causing said device to produce high frequency oscillations solely by means of energy supplied by a low frequency signaling wave and transmitting the oscillations thus produced.

28. The method of operating a signaling s 'stem which comprises an electron dis-. c arge device having grid and plate circuits coupled together for producing oscillations which consists in supplying to the plate circuit of said device a low frequenc' signaling wave only and thereby causing t e production of high frequency oscillations by means of energy derived solely from said low frequency signaling wave andtransmitting the highifrequency oscillations thus produced. 1

the combination of a source of low frequency i alternating modulating signal waves, an electron discharge device having plate and grid circuits coupled together for producing high frequency oscillations, and means orcausing saidv device to produce high frequency oscillations solely from energy supplied by said low frequency source.

In witness whereof, I have hereunto set my hand this 30th day of J anua 1919.

t WILLIAM C. ITE. 

